Automatic coal burner



Feb,6,1934. W, B. EDDISOIN 1,946,201

AUTOMATIC COAL BURNER Fil ed March 1927 moo o 000' L a i coooc juvcmfoz W'Hz'am Barian Eddison Patented Feb. 61,1934

. 'UNITED STATES AUTOMATIC COAL BURNER William Barton Eddison,

Ardsley on Hudson,

N. Y., assignor, by mesne assignments, to Henry M. Brooks, New Gardiner, Augusta, ley Hawes, Fall River,

Application March 1927.

12 Claims.

My invention is concerned with forced draft coal burners intended for domestic use, though the principles which will be hereinafter disclosed may be applied successfully 5- in other forced draft burners.

An objection to the use of coal burners in the heating of homes has been that the blower usually employed with such burners impresses'a slight back pressure upon the coal within the hopper,

or before discharge into the furnace, so that gas conveying fine, impalpable coal dust is carried backward through the coal mass, and, carried on rising air currents, these permeate the house, any burned or unburned furnace gases that may be 15 carried out this way fouling the air and the dust settling upon furniture, floors and furnishings. The chief object of my invention is to overcome this difliculty and so to control the operation of such a coal burner that the tendency to discharge so this gas and fine coal dust is overcome.

As a further object, it is my intention to provide a means for accomplishing the results indicated which is extremely simple and which requires no attention, but which automatically operates so long as the burner itself is in operation.

My invention comprises the novel parts and the novel combination and arrangement thereof, as shown in the accompanying drawing, described in the specification, and particularly defined by the-claims terminating the same.

In the accompanying drawing, 1 have shown my invention employed informs now preferred by me and associated with a standard type of automatic coal burner.

Figure 1 is an end elevation of a fuel feed means for burners, together with associated apparatus, the hopper being broken away and parts thereof being shown in section to illustrate the connection of my invention thereto.

,0 Figure 2 is a side elevation ofthe same installation, showing it connected to the burner.

Figure 3 is a cross section on the line 3-3 of Figure 1. v

' Figure 4 is a view similar to Figure 2, illustrating a slight modification.

The objection to automatic coal burners of the i type employing a blower for supplying air to the burner, and as mentioned above, consisting of the throwing off of gas and fine coal dust, has long been recognized. It has not been clearly understood why this gas and dust are thrown off, but I have discovered that this is due to the fact that the air which is delivered under pressure from the blower to the burner, creates a back flow through the coal feed conduit, the air conduit most particularly 3 York, N. Y., William Tudor Maine, and Richard Kings- Mass., as trustees Serial No. 173,037

and coal conduit being in effect in communication with each other. From the coal conduit the almost imperceptible back pressure flows through the coal hopper to the free air within the basement. The existence of a slight pressure in the coal conduit, in excess of atmospheric pressure, results in the very finest of the coal dust being blown outward from the mass as this pressure escapes from the surface of the coal, and burned and unburned gases resulting from the combustion may likewise be caused to flow back through the conduit and escape at the same place. These are then picked up by the usual convection currents and eventually distributed throughout the house.

To counteract this tendency I have applied to the coal supply system a negative pressure of such extent and character, and so applied, that it neutralizes or overcomes the slight pressure caused by thebacking upof air pressure from the fan. This results in drawing off the gas and dust, which arethen disposed of; I have found it convenient to discharge them into the furnace.

This negativepressure may be applied in a variety of ways, but I have found it convenient and simple to form a chamber within the compartment, or hopper so called, receiving the coal and from which the coal is furnished to the burner, this chamber being preferably submerged below, but freely open tothe coal mass within the compartment or hopper, and connected by a suitable conduit with the suction side of the fan which supplies air to the burner. By this means the suction within the chamber attracts the 'escaping gas and coal dust, as it were, and this gas and coal dust are returned to'the blower and thence to the burner, where both are consumed. In other words, the slight positive air pressure tending to discharge the gas and coal dust is intercepted before they can pass outward from the surface of the coal mass, and because of the slight negative pressure the gas and dust pass to the source .of the suction rather than out of the hopper top, and thence are passed out of the house.

Various forms of apparatus are shown for carrying out this method and for accomplishing the result indicated. In Figures 1, 2 and 3, I have shown a form of apparatus which has been found satisfactory; In the drawing the hopper 1 is 105 shown as communicating with a coal feed conduit 10 leading to the burner-2 and the blower 3 is shown with its outlet 29 communicating through a conduit 30 to the same burner 2; at the burner the combustion air under pressure passes into the 110 coal mass through the perforations in the grate 'duit 41 as'co'mmunicating, with the hopper at a point well below the surface of the therein. This location of the chamber has the "advantage that the mass of coal may be considand theblower, and at 34 a base for the burner. Asthusfar described the'drawing illustrates a conventionalized form of stoker or'coal burning apparatus; The burner and hopper are relative- 1y remote from each other (customarily a matter of a very few feet, the burnerbeing located in a furnace and the hopper outside the furnace), but the resultof connecting the air and coal conduits both to the same burner is that the blower incidentally functions to cause back pressure through the coal conduitiand hopper, in addition to its intended function of supplying airfor combustion. Suitable feed means are provided within the conduit 10, or'associated with 'the hopper, for" advancing coal from the hopper to the burner, and these feed means are driven through gearing indicated at 11. .A motor 12 serves as the source of power for the drive means 11 and for the blower 3, although of course it will be understood that various drive meansand various arrangements of the several elements may be employed.

Within the hopper 1 a chamber is formed by means of 'an inverted 'channel4 in such a way that the chamber 40 is ordinarily submerged beneath the surface of the coal mass within the hopper, but so that a negative pressure within the chamber 40 will be communicated through the coal mass and will serve to attract to this chamber any-gas and dust tending to be forced outward through the coal mass. This is best shown in Figure 3. In addition therewill be a tendency for air to pass downward through the surface of the coal mass and into the chamber 40, thus reversing the normal direction of .flow at the surface of the coal mass, intercepting any contained gas and withdrawing any loose coal dust, whereas under other conditions the tendency is to discharge such dust. For the purpose of creating a suctionwithin the chamber, aconduit 41 is connected to the channet i, forming the chamber, and leads thencelto the suction inlet 31 of the fan. The suction need not be strong, as the pressure-it must neutralize is extremely slight. I have found that most satisfactory results obtain when the chamber 40 is formed near the surface of "the coal mass, as thispermits the downward suction onthe mass described above. However, it will serve as well to intercept back pressure on the mass to bury the chamber more deeply. Thus, in Figure 4 I have shown the concoal mass erably depleted and the arrangement will still operate satisfactorily.

It is not to be understood thatthe device will not'operate'satisfactorily unless the chamber 40 is completely submerged beneath the surface of the coal. However, if the chamber 40 be open to the atmosphere abovethe coalmass a greater suction may be required than is necessary other! wise, and there will be a tendency to remove from"- the 'coalmass dust which would ordinarily advance with the solid coal. The result may be a delivery to the blower and air conduit of more coal dust than desirable. Of course, if a means other than the blower be employed as the source of suction, this objection may. largely lose its force.

It is immaterial whether the hopper 1 is uncovered, as shown in Figure 4, or is provided with a cover 14, as shown in Figures 1, 2 and-3.

extending from the blower to said burner, and a tween the chamber 40 and the burner 2.

' What I claim as my invention is:

1. The combination with a coal burning apparatus of the kind described including a burner to. support the burning coal, means creating a. I

suction including a blower to provide combustion air, a conduit'for the combustion air extending from the blower to said burner, and a coal supply system comprising means remote from the burner to furnish coal, a second conduit, said second conduitextending from said coal-furnishing gmeans to said burner, and means for feeding coal through said second conduit from the coal-furnishing means to the burner, of means providing a passageway leading fromsaid coal supply system to said suction creating means. a 2. The combination with a coal burning apparatus of the kind described'including a burner to support the burning coal, means creating a suction and including, a blower to provide cornbustion air, a conduit for the combustion'air extending from the blower to said burner, and a coal supply system comprising a coal compartment remote from the burner, a second conduit, said second conduit'extendirig from said compartment to said burner, and means'for feeding coal through saidsecond conduit from said compartment to the burner, of'means providing a I passageway *leading from adjacent the top of said compartment to said suction creating means. 110

3. The combination with a coal burning apparatus of the kind described including a burner to support the burning coal, a blower to provide combustion 'air, a conduit forthe combustion air coal supply system comprising means remote from the burner, to furnish coal, a second conduit, said second conduit extending from said coal-furnishing means to said burner, and means for feeding coal through said second conduit from said coal -iurnishing means to the burner, of means providing a passageway leading from said coal supply system to the suction inlet of said blower.

4. The. combination with a coalburning apparatus of the kinddiescribed including a burner ,to support the burning coal, a blower to provide combustion air, a conduit for the combustionair extending from theblower to said burner, and a coal supply system comprising a coal compartment remote from the burner, a second conduit, said second conduit extending from said compartment to said burner, and means for feeding coal through said second conduit from the compartment to the burner, of means providing a passageway leading from said compartment to the suction inlet of said blower,

5. The combination with a coal burning apparatus cf the kind described including a burner to support the burning coal, a blower to provide combustion air, a conduit for the combustion air extending from the blower to said burner, and'a coal supply system comprising a coal compartment remote from the burner; a second conduit, said second conduit extending from said compartment to said burner, and means for feeding coal through said second conduit from the compartment to the burner, of means providing a passageway leading from adjacent the upper end of the compartment to the suction inlet of said blower.

6. The combination with a coal burning apparatus of the kind described including a burner to support the burning coal, a blower to provide combustion air, a conduit for the combustion air extending from the blower to said coal supply system comprising a coal compartment remote from the burner, a second conduit, said second conduit extending from said compartment to said burner, and means for feeding coal through said second conduit from the compartment to the burner, of means providing a passageway leading to the suction inlet of said blower from a point within said compartment which is below a normal surface of coal in said compartment.

7. The combination with a coal burning apparatus of the kind described including a burner to support the burning coal, means creating a suction and including a blower to provide combustion air, a conduit for the combustion air extending from the blower to said burner, and a coal supply system comprising a coal hopper remote from the burner, a second conduit, said second conduit extending from the hopper to said burner, and means for feeding coal through said second conduit from the hopper to the burner, of means pro viding a downwardly opening chamber at the hopper, and means providing a'passageway from said chamber to said suction creating means.

8. The combination with a coal burning apparatus of the kind described, including a burner to support the burning coal, means creating a suction and including a blower to provide combustion air, a conduit for the combustion air extending from the blower to said burner, and a coal supply system comprising a coal hopper remote from the burner, a second conduit, said second conduit extending from the hopper 'to said burner, and means for feeding coal through said second conduit from the hopper to the burner, of means providing a trough-shaped channel opening downburner, and a.

wardly extending substantially across said hopper adjacent the upper end of the latter, and means providing a passageway from said channel to said suction creating means.

9. The combination with a coal burning apparatus of the kind described, including a burner to support the burning coal, a blower to provide combustion air, a conduit for the combustion air extending from the blower to said burner, and a coal supply system comprising a coal hopper remote from the burner, a second conduit, said second conduit extending from the hopper to said burner, and means for feeding coal through said second conduit from the hopper to the burner, of means providing a downwardly opening chamber adjacent the upper end of the hopper, and means providing a passageway from said chamber to the suction inlet of said blower.

10. The combination with a coal burning apparatus of the kind described, including a burner to support the burning coal, a blower to provide combustion air, a conduit for the combustion air extending from the blower to said burner, and a coal supply system comprising a coal hopper remote from the burner, a second conduit, said second conduit extending from the hopper to said burner, and means for feeding coal through said second conduit from the hopper to the burner, of means providing a trough-shaped channel opening downwardly extending substantially across said hopper, and means providing a passageway from said channel to the suction inlet of said blower.

11. The subject matter of claim 10, characterized by the fact that the bottom of said channel is lower than the surface of the coal when the hopper is filled.

12. The subject matter of claim 10, characterized by the fact that said channel is located adjacent the top of the hopper but the bottom of the channel is lower than the surface of the coal in the hopper when the hopper is filled.

WILLIAM BARTON EDDISON. 

